The human body is engineered for strength, power and endurance. Bone is sturdy as concrete but flexible enough to resist breaking. It's even light enough to allow us to be quicker off the mark than a racehorse.

The human body is engineered for strength, power and endurance. Bone is sturdy as concrete but flexible enough to resist breaking and light enough to allow us to be quicker off the mark than a racehorse. Our muscles, ligaments and joints have far greater strength and endurance than we know. In this episode, we feature extraordinary tales of human strength told with stunning see-through "anatomy in motion."

A young man is sucked up into a tornado, only to be spat out a quarter of a mile away, unharmed. Pinned by a massive boulder, a climber finds the strength to lift it off in a seemingly impossible muscular feat. A college football player sustains what would normally be unbearable injury and pain, yet has the mental stamina to continue playing at full output.

Plus, how does a swimmer tap the remnants of our distant ancestors' extraordinary stamina to swim across the English Channel in 14 hours? How do marathon runners keep the pace on their grueling 26-mile run?

Sight is the king of the senses. More than 80 percent of what we know of the world comes through our eyes -- without our sight we're lost. In this episode, we reveal the inner workings of our visual system as they've never been seen before, vividly confirming that ancient human adaptations prove no less crucial in modern life. The astounding hidden powers in our eyes are brought to life by true stories including:

A patrolman relies on the power of sight as he risks his life in a high-speed chase of a murder suspect.

A firefighter crawls through thick smoke in a burning building to seek survivors using innate night vision and clues decoded by his brain's vision center.

A lifeguard applies his remarkable skills of pattern recognition to spot one drowning man amid thousands at the beach.

Plus, how do magicians fool us with their illusions? What lies behind the mysteries of our dreams? And what new powers will be discovered by the latest scientific breakthroughs enabling doctors to plug a camera directly into the brain?